

// #iChannel0 "file://../effects/home_bg.jpg"
#iChannel0 "file://../effects/lv_1.png"

// iResolution  已知
// iTime 已知
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
      
    vec2 tapPoint = vec2(iMouse.x/iResolution.x,iMouse.y/iResolution.y);

    vec2 st = fragCoord/iResolution.xy;
    vec3 color = vec3(0.0);

    vec2 dv =  vec2(0.5) - st;
    dv *= iResolution.x/iResolution.y;
    float dist = length(dv);
    dv = normalize(dv);


    vec2 dv2 = tapPoint - st;
    dv2 *= iResolution.x/iResolution.y;
    float dist2 = length(dv2);
    dv2 = normalize(dv2);
    float sinFactor2 = sin(20. * dist2 + iTime) * 0.01;

    float sinFactor = sin(20. * dist + iTime) * 0.001;
    vec2 offset = dv * sinFactor + dv2 * sinFactor2;
    fragColor = texture(iChannel0,st + offset);
}